James f



(No Model.)

J. P. MCELROY. ELEGTRIG HEATER.

No. 588,640. Patented Peb. 8', 1888.

El-g-fwfvvvw--f- [E l :n 2 m l A lfm/ENTER WITNEEEEE m8887888? UNITED STATES PATENT OFFICE.

JAMES F. MCELROY, OF ALBANY, NEV YORK, ASSIGNOR TO THE CONSOLI- DATED CAR-I-IEATING COMPANY, OF SAME PLACE.

HEATER.

SPECIFICATION forming part of Letters Patent No. 598,640, dated February 8, 1898.

Original application filed April 6, 1895, Serial No. 544,727. No. 647,347.

To @ZZ whom, it 77mg/ concern:

Be it known that I, JAMES F. MCELEOY, a citizen of the United States, residing in the cityand countyof Albany, Stateof New York,

have invented a new and useful Improvement in Electric Heaters, of which the following is a speciiication.

My invention relates to improvement-s in devices for heating by electricity; and the Io object of my invention is to provide a compressible heater-frame about which a resistance may be wound and which will adapt itself to the pressure of the Wirecaused by the expansion and contraction thereof. I aci 5 complish this object by means of t-he mechanism illustrated in the accompanying drawings, in Which- Figure l is an elevation. Fig. 2 is an end view of Fig. l, and Fig. 3 is a cross-section 2o along the lines 2 2 onA Fig. l.

Similar letters refer to similar parts throughout the several views.

Ordinarily the frame of an electric heater has been made rigid and the wire wound upon the frame is on a practically incompressible insulator. The result has been that when a current has been passed through the wire, heating it to a very high temperature, the expansion of the wire causes it to buckle, be-

come loose upon the frame, and in many cases to short-circuit. It is to obviate this difficulty and to maintain a constant and even pressure at all times upon the resisting-wire that I have constructeda compressible frame l3 5 so arranged that when the wire expands with heat the frame also expands, thus maintaining a constant and even tension on the wire. This tension should be sufficient to keep the wire stretched, but not in any way to injure 4o its life while heated. As the wire cools and contracts the frame will yield sufficiently to maintain an even tension on the wire.

Divided and this application led August 6, 1897. Serial (No model.)

A division having been required by the examiner in charge of my application for patent filed April 6, 1895, Serial No. 544,727, in which a description of the invention herein was origin ally set forth, as a modified form this application is made.

Referring to the drawings, I construct the frame H II in two parts, adj ustably held to- 5o gether by the bolts K K, each part of the vframe provided with an insulator L L at its edge, and the two parts capable of moving slightly upon each other by means of the slots 7.; 7o and the bolts K K, passing through them. 5 5 At the ends of the heater I place the coiled springs M M around the rods m m, each of said springs having one end resting against one portion of the frame II and the other end resting against the otherportion of said frame 6o H and adjustable in such a manner that as the halves of the frame are drawn together the springs M M will become compressed. Around the insulators L L, I wind the wire IY.

lVhen the wire becomes heated, it expands, and the springs M will keep the insulators in contact with the wires, preventing bunching and short-circuiting. When the wires become cool and contract, the frame will become compressed by the action of the wires 7o against the tension of the springs.

What I claim as my invention, and desire to secure by Letters Patent, is-

An electric heater comprising incombination two overlapping plates adapted to slide 7 5 relative to each other and provided with insulating edges, means for connecting the plates together, springs arranged between the plates tending to force them apart, and a resistance-wire wound around the plates.

JAMES F. MCELROY. Witnesses CHAs. B. MircHELL, MARY AGNES BURKE. 

